Treatment of erectile dysfunction and lower urinary tract symptoms by phosphodiesterase inhibitors

Pentaclethra macrophylla leaves reduce blood glucose level, improve sexual behavior and modulate critical enzymes associated with diabetes-erectile dysfunction morbidity in rats

OBJECTIVES

This research work studied the phenolic composition of Pentaclethra macrophylla (PM), the inclusion of dietary supplementation of PM leaves on sexual functions and its connection to inhibit enzymes (arginase and phosphodiesterase-5) and nitric oxide level, linked to type 2 diabetes-induced erectile dysfunction in rats.

METHODS

Gallic acid, chlorogenic and ellagic acids, Kaempferol, and epicatechin etc. was spotted with High performance liquid chromatography-diode array detector from PM extract. Twenty-five (25) rats were used for the study. Five rats were placed with basal diet; diets not supplemented with PM leaves (normal rat group) while twenty rats were made diabetic by feeding them with high fat diet for two weeks, prior to single injection with 35 mg/kg of streptozotocin (STZ). After checking with glucometer, experimental animals with blood glucose level >250 mg/dL were accepted as diabetic. The diabetic rats were subsequently divided into four groups of five rats each (n=5). The diabetic rats were placed on basal diet, or diets supplemented with PM leaves (10 % or 5 % inclusion) or sildenafil citrate (SC).

RESULTS

The result revealed that PM supplemented diets caused significant (p<0.05) reduction in blood glucose level, and augmented erectile function by inhibiting arginase and PDE5 activities as well as enhancing nitric oxide level.

CONCLUSIONS

In conclusion, dietary inclusion of PM leaves could serve as a potent nutraceutical source in hyperglycemia induced erectile dysfunction management.

Beyond Erectile Dysfunction: cGMP-Specific Phosphodiesterase 5 Inhibitors for Other Clinical Disorders

Cyclic guanosine monophosphate (cGMP), an important intracellular second messenger, mediates cellular functional responses in all vital organs. Phosphodiesterase 5 (PDE5) is one of the 11 members of the cyclic nucleotide phosphodiesterase (PDE) family that specifically targets cGMP generated by nitric oxide-driven activation of the soluble guanylyl cyclase. PDE5 inhibitors, including sildenafil and tadalafil, are widely used for the treatment of erectile dysfunction, pulmonary arterial hypertension, and certain urological disorders. Preclinical studies have shown promising effects of PDE5 inhibitors in the treatment of myocardial infarction, cardiac hypertrophy, heart failure, cancer and anticancer-drug-associated cardiotoxicity, diabetes, Duchenne muscular dystrophy, Alzheimer's disease, and other aging-related conditions. Many clinical trials with PDE5 inhibitors have focused on the potential cardiovascular, anticancer, and neurological benefits. In this review, we provide an overview of the current state of knowledge on PDE5 inhibitors and their potential therapeutic indications for various clinical disorders beyond erectile dysfunction.

PDE5 inhibitors - pharmacology and clinical applications 20 years after sildenafil discovery

The discovery of the nitric oxide/cGMP pathway was the basis for our understanding of many normal physiological functions and the pathophysiology of several diseases. Since the discovery and introduction of sildenafil, inhibitors of PDE5 have been the first-line therapy for erectile dysfunction (ED). The success of sildenafil in the treatment of ED stimulated research in the field of PDE5 inhibition and led to many new applications, such as treatment of lower urinary symptoms, and pulmonary arterial hypertension, which are now approved indications. However, PDE5 inhibitors have also been used in several other disorders not discussed in this review, and the fields of clinical use are increasing. In the present review, the pharmacological basis of the NO/cGMP pathway and the rationale and clinical use of PDE5 inhibitors in different diseases are discussed.

Effects of daily tadalafil on lower urinary tract symptoms in young men with multiple sclerosis and erectile dysfunction: a pilot study

PURPOSE

Men affected by multiple sclerosis often experience neurogenic overactive bladder (OAB), lower urinary tract symptoms and erectile dysfunction (ED). The aim of the study was to investigate modifications of urinary and sexual functions after administration of daily tadalafil (TAD) 5 mg.

METHODS

Twenty men were enrolled in a single-blind, 4-week prospective study while 10 men without treatment served as controls. Primary outcomes were changes from baseline of International Prostate Symptom (IPSS), OAB questionnaire (OAB-q-short form) and International Index of Erectile Function (IIEF-5) scores. To evaluate the influence of bladder filling on somatic reflexes, we studied variations of the H-reflex evoked by electrical stimuli applied to the tibial nerve at the popliteal fossa and recorded from the soleus muscle. Also testosterone/estradiol (T/E) ratio was measured before and after treatment.

RESULTS

In TAD group, an improvement in IPSS (p < 0.001), OAB-q (p < 0.001) and IIEF-5 (p < 0.001) scores was found. Also, an increase in Q _max (p < 0.01) and T/E ratio (p < 0.01) was found with a concomitant reduction in post-void residual volume (p < 0.001) without any changes in the H-reflex.

CONCLUSIONS

The study demonstrates for the first time that daily TAD in patients with multiple sclerosis improves storage symptoms, post-void residual volume, steroid hormone pattern and ED without urodynamic changes.

A review of analytical methods for the determination of four new phosphodiesterase type 5 inhibitors in biological samples and pharmaceutical preparations

The introduction of oral phosphodiesterase type 5 inhibitor therapy in 1998 revolutionized the treatment of erectile dysfunction. Erectile dysfunction is the most common sexual problem in men. It often has a profound effect on intimate relationships and quality of life. The analysis of pharmaceuticals is an important part of the drug development process as well as for routine analysis and quality control of commercial formulations. Whereas the determination of sildenafil citrate, vardenafil and tadalafil are well documented by a variety of methods, there are few publications about the determination of udenafil, lodenafil carbonate, mirodenafil and avanafil. The paper presents a brief review of the action mechanism, adverse effects, pharmacokinetics and the most recent analytical methods that can determine drug concentration in biological matrices and pharmaceutical formulations of these four drugs.

Common theme for drugs effective in overactive bladder treatment: inhibition of afferent signaling from the bladder

The overactive bladder syndrome and detrusor overactivity are conditions that can have major effects on quality of life and social functioning. Antimuscarinic drugs are still first-line treatment. These drugs often have good initial response rates, but adverse effects and decreasing efficacy cause long-term compliance problems, and alternatives are needed. The recognition of the functional contribution of the urothelium/suburothelium, the autonomous detrusor muscle activity during bladder filling and the diversity of nerve transmitters involved has sparked interest in both peripheral and central modulation of overactive bladder syndrome/detrusor overactivity pathophysiology. Three drugs recently approved for treatment of overactive bladder syndrome/detrusor overactivity (mirabegron, tadalafil and onabotulinum toxin A), representing different pharmacological mechanisms; that is, β-adrenoceptor agonism, phosphodiesterase type 5 inhibition, and inhibition of nerve release of efferent and afferent transmitters, all seem to have one effect in common: inhibition of the afferent nervous activity generated by the bladder during filling. In the present review, the different mechanisms forming the pharmacological basis for the use of these drugs are discussed.